This invention relates generally to motors and more particularly to an inductive linear dc (direct current) electric motor.
In linear dc motors, voltages are generated in windings or groups of coils by sending current through the windings and placing the windings in a magnetic field. The more uniform the magnetic field the more efficient and the more accurate the motor can be.
A group of coils interconnected so that their generated voltages all make a positive contribution to the desired result is called an armature winding. The armature winding of a dc motor is the rotating or moving member, or rotor. In general these coils are wound on iron cores. This is done to maximize the coupling between coils, to increase the magnetic energy density associated with the electromechanical interaction, and to shape and distribute the magnetic fields according to the requirements of each particular motor design.
Analysis of dc motors shows that associated with both the rotor and stator are magnetic flux distributions which are fixed in space. It also shows that the force-producing characteristics of the dc motor stems from the tendency of these flux distributions to align. An induction motor, despite fundamental differences, works on exactly the same principle; one can identify flux distributions associated with the rotor and stator, which move in synchronism and which are separated by some force-producing displacement.
DC motors are generally much more adaptable to adjustable-speed service than the ac motors associated with a constant-speed rotating field. The susceptibility of dc motors to adjustment of their operating speed over wide ranges by a variety of methods is one of the important reasons for the strong competitive position of dc machinery in modern industrial and commercial application.
An example of a linear dc electric motor can be found in French Patent No. 2510839 to Belikov et al. The problem with this motor, is that there is too much power wasted due to the lack of uniformity of the magnetic field.
Another example of dc motors can be found in USSR Patent No. 1494162 to Belikov et al. This inductive linear dc motor includes a rotor having two concentrators, framed by permanent magnets. The problem with this motor is reduction of the value of magnetic induction of the main fields in the areas of air clearance remote from the longitudinal axis of the moveable element (the rotor).
Thus there exists the need for an efficient induction linear electric dc motor in which the magnetic field is more uniformly distributed through the armature winding.
It is accordingly an object of the invention to provide an induction linear electric direct current motor.
It is another object of the invention to provide an induction linear electric direct current motor that provides more uniformly distributed magnetic fields to the armature winding.
It is a further object of the invention to provide a more efficient induction linear electric direct current motor.
It is yet another object of the invention to provide a more accurate induction linear electric dc motor.